Projectiles, such as missiles, rockets, and the like, are launched from various types of launch tubes (e.g., canisters, guns, one or more cells of a vertical launching system (VLS), torpedo tubes, etc.). In some projectile systems, thrust from a thrust source in the form of an integrated projectile motor or propellant carried by the projectile is used to launch the projectile from the launch tube. However, using the thrust generated internally by the projectile thrust to launch the projectile (i.e., a hot launch), reduces the amount of fuel for the motor or propellant available to propel the projectile to an intended target after the projectile leaves the launch tube.
In response to this problem, some projectile systems employ a launching propellant, which is separate from the projectile's propellant, to launch the projectile from the launch tube and to provide an initial velocity to the projectile (i.e., a cold launch). For example, projectile systems may include a projectile disposed in a launch tube with a launching propellant and a pusher plate, which may also be characterized as a ram plate, positioned at the aft end of the projectile in the launch tube. When the projectile is to be launched from the launch tube, a propellant igniter is activated to ignite the propellant. Expanding gases generated by the burning propellant push the plate and the projectile out through the open end of the launch tube. The thrust source carried by the projectile (e.g., a motor and/or propellant) may then be initiated to further accelerate the projectile and propel it to its intended target.
In many applications, it is desirable to minimize the size and cost of the overall projectile system including the projectile, launch tube, and launching propellant. However, the selection, volume, and configuration of the launching propellant deployed within a launch tube may require reinforcing the launch tube, pusher plate (where implemented), and projectile because gas pressure and heat from the burning propellant may damage these components, causing launch failure or decreasing the likelihood that components of the projectile system may be reused. Unfortunately, such reinforcements of the components of the projectile system may increase the cost, size, and overall weight of the projectile system. Further, in order to propel the projectile at a selected rate of acceleration and velocity, the selection, volume and configuration of the launching propellant (e.g., the use of multiple initiators and gas generants) may require excessive space in the launch tube, add to the overall size, weight, and cost of the launch tube, and may require the use of complex initiation systems and relatively expensive gas generants.